1. Field of the Invention
The present invention relates generally to a post-CMP wafer cleaning apparatus. More particularly, the present invention relates to a scrubber cleaner used in the cleaning of semiconductor wafer substrates after a CMP process.
2. Description of the Prior Art
As known in the art, chemical mechanical polishing (CMP) techniques are used for planarizing material layers on a wafer in semiconductor industry. Typically, in a CMP process, an abrasive suspension agent or slurry is dispensed onto a polishing surface of a polishing pad. Relative movement between the polishing surface and the wafer produces a combined mechanical and chemical effect on the surface of the wafer. This process creates a highly level surface on the wafer.
In order to remove residual slurry and other residues from the polishing process, post-CMP cleaning steps are required. One of the cleaning steps carried out after the CMP process is facilitated using rotating scrubber brushes which are actuated inside a scrubber cleaner. A combination of rotational movement of the brush and force or pressure placed on the brush against the wafer causes the residual slurry to be removed from the surface of the wafer.
However, the prior art post-CMP wafer cleaning apparatuses cannot provide satisfactory cleaning efficiency. Slurry residues and High defect count are observed along the perimeter of the wafer surface. Accordingly, there is a need in this industry to provide an improved post-CMP wafer cleaning apparatus that is capable of addressing such issue.